Recent studies have exponentially increased the number of known noncoding RNA categories, including microRNA (miRNA), small interfering RNA (siRNA), PIWI element-interacting RNA and various classes of long noncoding RNA (ncRNA), that fulfill key roles as transcriptional and post-transcriptional regulators and guides of chromatin-modifying complexes [1]. Among these short RNAs, miRNAs are post-transcriptional regulators of gene expression in a wide range of biological processes and diseases [2]. miRNAs are considered as prominent tumour markers, relevant targets for therapy and therapeutic agents [3]. Here, we discuss the discovery of a novel type of miRNA-related small RNA, miRNA–offset RNA (moRNA), whose function is currently unknown.

Recent studies have exponentially increased the number of known noncoding RNA categories, including microRNA (miRNA), small interfering RNA (siRNA), PIWI element-interacting RNA and various classes of long noncoding RNA (ncRNA), that fulfill key roles as transcriptional and post-transcriptional regulators and guides of chromatin-modifying complexes [1]. Among these short RNAs, miRNAs are post-transcriptional regulators of gene expression in a wide range of biological processes and diseases [2]. miRNAs are considered as prominent tumour markers, relevant targets for therapy and therapeutic agents [3]. Here, we discuss the discovery of a novel type of miRNA-related small RNA, miRNA–offset RNA (moRNA), whose function is currently unknown.